
Creating a disk image
You can use Disk Utility to create a disk image of a disk, volume, or folder. You can use disk images to move files from one computer to another or to send to other people in email messages.
You can also use a disk image to burn a CD or DVD disc to send to other people or to back up the contents of your disk so that you can restore it if something happens to your information.
When you create a disk image you choose the format of the image:
- Choose "compressed" to save space.
- Choose "read only" to prevent the contents of the disk image from being changed.
- Choose "read/write" to allow changes to the disk image.
- Choose "DVD/CD master" to create a disk image you can use to make copies on DVD or CD discs.
You can also create a blank disk image so that you can copy files to it later. See "Creating a blank disk image" for more information.
- If the files you want in the disk image are in different locations, move them to a folder or volume before you begin.
- To create a disk image from a disk or volume, select it in the list of disks and volumes.
- Choose File > New then the type of image you want to create.
To create a disk image from a folder, choose “Disk Image from Folder.” Select the folder you want, then click Image.
To create a disk image from a disk or volume, choose "Disk Image from disk name."
- Type a name for the image and choose where you want to save the image.
- Choose one of the disk formats from the Image Format pop-up menu.
- To require a password to access the contents of the image, choose "AES-128 (recommended)" from the Encryption pop-up menu.
- Click Save.
- If you are creating an encrypted disk image, enter the password when you are asked.
The name of the disk image is followed by the filename extension ".dmg."